Automatic telephone system.



k I/I/I'INESSES C. E. ROGERS.

AUTOMATIC TELEPHONE SYSTEM,

APPLICATION FILED 050.12. 1913.

Patented Feb. 20,1917.

2 SHEETS-SHEET I.

MENTOR I D cf ceuc C? UNITED STATES PATENT OFFICE.

CLARE NOE E. ROGERS, OF OAKLAND, CALIFORNIA, ASSIGNOR T AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION ILLINOIS.

AUTOMATIC TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Feb. 20, 1917.

Application filed December 12, 1913. Serial No. 806,281.

phone Systems, of which the following isa specification.

My invention relates to improvements in automatic telephone systems, and has for its object the provision of improved means for uniting into one system two-wire and threewire apparatus in such a manner that a connection from either a two-wire or a three-wire suhscribcfs line can be extended to the central olliee over the same trunk line and either of said subscribers can employ the same central office equipment. More specifically, my invention relates to the provision of repeating mechanism which is interposed in the trunk line between the automatic switches at the central office and the subscribers lines, so that these automatic switches can be operated by impulses sent from the subscribers lines either over two sides of the line in series, or by impulses from the subscribers lines Over the two sides of the line and ground.

My invention will be more clearly understood by reference to the accompanying drawings, in which I have illustrated my invention in connection with certain wellknown forms of automatic switches.

It will, of course, be understood that various forms of line switches and selectors could be employed in place of the ones I have illustrated, and likewise thatthe completion of the connection from the selector to the called line could be accomplished in any well-known manner, either through further automatic switches or through a manual operators board.

In the drawings Figures 1 and 2 taken together represent diagrammatically a portion of the central otlice apparatus necessary for completing a connection between a calling subscriber and :1 called subscriber.

Fig. 1 shows a substation A and a. substation A, together with their individual switches C and C, which are under the control of the common mechanism or master switch D. The line switches C and C belong to a group of similar line switches, the plungers (not shown) of which engage a shaft and are controlled by the operation of the master switch D in such a manner that they are, when in normal position, held directly 1n front of an idle trunk line.

Fig. 2 represents a trunk line leadingfrom the above-mentioned group of line switches through a repeater I to a first selector E.

The automatic substations with which I have chosen to illustrate my invention are of two types. The substation A is of the type in which the impulses are transmitted to the central ofiice over two sides of the line separately with a. ground return-that is. the usualform of three-wire substation. This substation comprises the usual receiver 2. the switch-hook 3, the transmitter 4,

ringer 5 and the condenser 6. This substation is likewise provided with an impulse transmitting device comprising the impulse wheel 11 provided with ten so-called vertical impulse teeth 12 and one rotary impulse tooth 13. These teeth are so arranged that as the impulse wheel is rotated forward through the medium of the dial (not shown), the rotary tooth 13 forces the socalled rotary impulse spring 14 into engagement with the ground spring 15, whereby the rotary line conductor 18 is given a preliminary impulse for operating the line switch 0. As the wheel 11 returns to normal position, the vertical impulse spring 17 is forced into engagement with the ground spring 15 a number of times corresponding to the digit called, after which the rotary spring 14 is once more forced into contact with the ground spring 15. While the impulses are being transmitted,-the connection between, the two sides of the line is broken between the springs 19 and 20, which come into engagement when the receiver is removed from the switch-hook, butare permitted to disengage by the dog 21 whenever the dial is out of norn'ial. position. As the switch-lumk is lowered, the cam arm 22 momentarily presses the release springs 23, 24 and 25 into engagement, whereby the substation line conductors may be grounded simultaneously. Means whereby a subscriber may signal a called subscriber comprises the push-button 26, which, when pressed, carries the spring 27 out of engagement with the contact point 28 and into engagement with the contact point 29, whereby the vertical line conductor 16 is grounded.

The substation A is somewhat similar to of similar sets.

the substation. A in. that .it likewise coin.- prises the usual receiver 2, switch-hook 3, transmitter 4, hell 5 and condenser 6. It is also provided with an impulse transmitter or calling device which is represented herein by a pair of impulse springs! and 8 and an impulse wheel 9, which latter is as sumed to be controlled through the medium of a finger hole dial (not shown) in such a manner that the impulse springs 7 and 8 may be momentarily separated a number of times corresponding to the digit called. The substation A is also provided with a push button 10 which, when depressed, applies ground battery to the substation line conductors.

The line switch C is similar to that type of line switch shown in British patent to R. W. James No. 26,301 of 1906. In its general form it comprises a trip magnet 30, a release magnet 31 and a bridge-cutoff relay 32. The trip magnet is designed to operate the usual plunger for pressing the bank springs 33, 34, 35 and 36 into engagement with their respective bank springs 37 38, 39 and 40, of which there are a number The plunger is so arranged that when in normal position it is under the control of the master switch D, whereby the said plunger may always be moved from opposite a seized trunk to a position opposite an idle trunk. The release magnet operates to restore the plunger to normal position. The bridge-cut-ofi relay 32 operates to disconnect the line switch from the substation trunk lines 18 and 16. Although only one set of springs (33 to 40) is shown in connection with the line switch C, each line switch is provided with a plurality of such sets, each set forming a terminal of a trunk line leading to a first selector E. Each trunk line is connected in multiple with the corresponding. springs of all the line switches of the group which is controlled by-the master switch D.

The line switch C is of the same general type as the line switch C, but is modified slightly to operate in a so-called two-wire system, 1,. (2., a system in which the impulses are delivered over the two sides of the line in series.

The master switch D is of the same general type as that disclosed in British patent to R. W. James No. 26,301 of 1906, above referred to. The function of the master switch, as is well known, is to maintain the plungers of all the idle line switches in position to engage the terminal of an idle trunk line.

The repeater I is placed in thetrunk line connecting the line switch bank terminals to the first selector E and is adapted to receive impulses from the two-wire substation A and repeat them to the switches in a three-wire exchange. The repeater I comprises,among other details, the doublewound relays 41 and 42 and the slow acting relays 43, 44, 45, 46 and 47. The slow acting relays 46 and 47 are connected in series and are so arranged that the relay 46 deenergizes quicker than the relay 47, thus operating to close the contact of springs 48 and 49 before the contacts of the springs 50 and 51 are opened.

The selector E is of the general type disclosed in United States Letters Patent No. 815,321, granted March 13, 1906, to Keith, Erickson and Erickson. In general it comprises the usual shaft (not shown) carrying the wipers 52, 53 and 54. This shaft has a vertical motion controlled by the vertical magnet 55 and a rotary motion con trolled by the rotary magnet 56. The private magnet 57 controls the side switch carrying the wipers 58, 59, 60 and 61 in the usual manner. The release of the switchmechanism is provided for in the releasemagnet 62.

Having gi-vcn a general description ofthe apparatus involved in the system, and in order to give a complete understanding of my'im'ention, I will now describe how the calling subscriber A, whose substation is of the three-wire type, may make connection with and operate the first selector E. Since the operation of the switching apparatus disclosed herein is in general well, known in the art, it is not thought necessary to describe its operation in detail, only sufficient description being given to enable a complete understanding of my invention. assume that the first digit of the desired number to be called is 2.

When the calling subscriber, after removing his receiver from the switch-hook, operates his calling device for the digit 2, the preliminary impulse over the rotary condoctor 18 passes through the springs of the cut-oil" relay 32 of the line switch C, and through the trip magnet 30, contact of the springs 63 to the battery lead 100 and thence through the battery B to ground G. The magnet 30, upon energizing, releases the plunger of the line switch C, allowing it to enter its bank, wherel'iy the line conductors l6 and 13 are extended through the line switch bank springs 33 and 37, and 3(3 and 40 through the repeater l' to the selector l). After the line switch (1 has operated, its master switch I) operates in a well-known manner to advance the plungers of the remaining line switches of the groi'ip to which the switch (7 belongs to an idle trunk line. The relay 64 of the repeater I is energized as soon as the ban k springs 34 and 38 n'iakc contact. The said circuit extends from ground (i through the relay 64 (Fig. 2). conductor (35, bank springs 38 and M and the release magnet 31 to the battery lead v100. The relay 64 is of a, rather high resist- We will ance and does not permit sufficient current to How to operativcly energize the release magnet- 31. The operation of the relay (34 is functionless at this time and therefore the line remains connected through to the selector E. I

After the connection has been thus extended to the first selector E, two impulses are transmitted from the substation A over the vertical line 16, conductor (36, springs (38 and (39 of the relay 43 and through the selector vertical line relay 70 to battery B, followed by one impulse over the rotary line 18, conductor 67, springs 71 and 72 of the relay 43 and through the selector rotary line relay 73 to battery B. The selector E operates in response to said impulses transmitted through its vertical and rotary line relays to extend the connection to an idle trunk line. Vhen the connection is thus extended to said trunk line. the usual guarding ground extended to its selector private bank contacts, extending from ground G" in the selector E through the side switch wiper 59 in third position), release relay 135, and the selector privatewiper 53 to the bank contact 70 and the corresponding contact in the hanks of all the selectors which have access to said trunk. After the connection has been completed, the release of the apparatus is brought about by the calling subscriber A replacing his receiver upon the receiverhook, thus causing the cam arm 22 to press the springs 23, 24 and into engagement momentarily, which action grounds the vertical and rotary trunk lines, causing the apparatus to release in a Well-known manher. The release circuit for the line switch C extends from ground Gr through the con tact of springs T 7 of the release magnet 02, over the trunk conductor 65, through the line switch springs 38 and 34 and the release magnet 31 to the battery lead 100.

It having been explained how the subscriber A may make connection with and operate the selector E over the trunk line 66, 67, it will now be explained how the subscriber A (whose substation is of the twowire type) may make connection with and. operate the same first selector E over the same trunk line. The subscriber A, upon removing his receiver 2 from the receiverhook 3, closes a bridge across the line conductors 78 and 79. The closing of this bridge across the line conductors establishes an energizing circuit for the trip magnet 80 of the line switch C. This circuit extends from ground G through the contact of springs 81 and 82, trunk line 78, through the substation A, return conductor 79, springs and 84, trip magnet 80, slow acting relay R5 and the contact of springs 63 to the battery lead 100. The magnet 80, upon energizing, releases the plunger of the line. switch C, allowing it to enter the bank and force the springs 80, 87, 88 and. 89 into contact with the springs 90, 91, 92 and 93, respectively. The engagement of the springs 90 and 93 by the springs 86 and 89 connects the substation lines 78 and 79 to the trunk conductors 66 and 67, respectively. After the line switch C has operated, its master switch D operates in the well-known manner to advance the plungers of the remaining line switches of the group to an idle trunk line. The, engagement of the bank springs 87 and 91 closes a circuit through the said relay 64. The said circuit extends from ground G through. the relay 64, conductor 65, bank springs 91 and 87 and the release magnet 102 to the battery lead 100. The relay 64 is of a rather high resistance and does not permit sufiicient current to flow to operatively energize the release magnet 102. The relay 8?) energizes in series with the trip magnet 80 and operates in conjunction'with the relay 64 to close a circuit through the relay 43 of the repeater I. The engagement of the bank springs 88 and 92 closes an energizing circuit for the cut-off relay 94 of the line switch C, which, upon energizing,breaks the circuit of the trip magnet 80 and the relay 85. The relay is slow acting and consequently does not de energize immediately after its energizing circuit is broken, but retains ground battery on the spring 98 of the relay 64 until the said relay 64 has energized. The circuit for the relay 43 extends from ground G through the contact of springs 96, conductor 97, contact of the springs 98, 99 and 101 and the relay 43 to battery B. The springs 98, 99 and 101 are adjusted to insure a long contact between the springs 98, 99 and 101 before the springs 99 and 101 break contact. The relay 43, upon energizing, closes a locking circuit for itself through. the springs 103 independent otits energizing circuit. A further result of the energization of the relay 4-3 is to disconnect the trunk conductors 00 and 67 from the conductors 104 and 105 and to bridge the relays 41 and 42 across the said conductors 66 and 67. The circuit of said relays extends from ground Gr through the upper winding of the relay 42, lower winding of the relay 41, contact of springs 107 and 72, trunk conductor 07, through the substation A, return trunk conductor 06, springs 106 and 68, upper winding of the relay 41 and the lower winding of the relay 42 to battery B. The relay 42 is differentially wound and consequently does not operatively energize at this time. The relay 41, upon energizing, closes acircuit for the relay 45. The said circuit ex tends from ground G through the contact of springs 112 and 113 and the relay 4:) to battery B. The apparatus is now in readiness to receive impulses from the substation A and repeat the same to the selector E.

The calling subscriber now operates his calling device for the digit 2, whereby the substation impulse springs 7 and 8 are separated twice momentarily, each time breaking the circuit of the line relay 41 of the repeater I. The relay 45 being slow acting does not deenergize during the momentary interruptions of its circuit by the line relay 41 and consequently each time the latter relay deenergizes, an impulse is transmitted o 'er the vertical trunk conductor 104 over a circuit extending from ground G through the contact of springs 112 and 111, springs 117 and 116, springs 118 and 119 and through the vertical line relay of the selector E to battery B. A further result due to the successive denergization of the relay 41 is to close a. circuit through the slow acting relays 46 and 47 in series. The said circuit-extends from ground Gr through the contact of springs 109 and 108, springs 120 and the relays 46 and 47 in series to battery B. The relays 46 and 47 remain energized during the entire time that the line relay 41 is operating to send impulses to the vertical line relay 70 of the selector E. After the last impulse has been delivered, the relay 46 denergizes. closing the contact of springs 48 and 49 before the contacts of springs 50 and 51 of the relay 47 open. The relay 47 then deenergizes, thus transmitting an impulse of current over the rotary trunk conductor 105 from ground G through the contact of springs 48, springs 50 and the rotary line relay 73 of the selector E to battery B. The selector E, receiving the two vertical impulses and the one rotary impulse, operates in the manner previously described to connect the conductors 104 and 105 to the trunk lines 74 and 75'.

After the connection from the trunk lines 74 and 7 5 to a called line has been completed in any desired manner, the calling subscriber presses the key 10 tosignal the called subscriber. The key 10, upon being pressed, grounds both the conductors 66 and 67. The grounding of said conductors retains the relay 41 energized and allows the relay 42 to be operatively energized. The relay 42, upon energizing, closes a circuit through the relay 44. The said circuit extends from ground G through the contact of springs 48, contact of springs 121 and the relay 44 to battery B. A further result of the energization of the relay. 42 is to close a circuit over the vertical trunk conductor 74 from ground G through the contact of springs 122 and 123, springs 124 and 119, over the conductor 104 and the conductor 74. If the usual connector switch is employed to complete the connection to the called line, the closure of this circuit will energize the vertical line relay of the connector, which in.

turn operates the ringing relay to apply ringing current to the called hne. The relay 44, upon energizing, closes a locking circuit for itself through the springs 125 independent of its energizing circuit and also bridges the resistance 127 across the conductors 104 and 105. The said circuit extends from the conductor 104 through the contact of springs 119 and 124, springs 123 and 128, springs 114 and 115, the resistance 127 and the springs 129 to the conductor 105.

' The replacing of the receiver on the hook 75 at the calling substation allows the switchhook to open the bridge across the line conductors 78 and 79, which permits the relay 41 to de'e'nergize. The relay 41, upon deenergizing, closes a circuit through the slow actin relays 46 and 47 in series and opensthe circuit of the relay 45. The energizing circuit for the relays 46 and 47 extends from ground G through the contact of springs 109 and 108, springs 120 and the'relays 46 and 47 in series to the battery B. The relay 45, upon denergizing, opens the circuit of the relays 46 and 47 at the springs 120. The relays 46 and 47, upon denergizing, operate to ground the trunk conductors 74 and 75 momentarily. The'ground for the con ductor 74 extends from ground (l through the contact of springs 112 and 111, springs 117 and 133, springs 49 and the springs 51 to the said conductor. The ground for the 95 conductor 75 extends from ground G through the contact of springs 48 and the springs 50 to the said conductor. The grounding of the conductors 74 and 75 would cause the connector switch to release in the well-known manner which in turn would cause the release relay 135 of the selector E, to close the circuit of the release magnet 62 for releasing said selector. The release magnet 62, upon energizing, closes the circuit of the release magnet 102 of the line switch 0 and thus all the apparatus is returned to normal position.

It will thus be seen that I have devised a very efiicient system in which a subscriber on either a line of the two-wire type or a line of the three-wire type may extend a connection over the same trunk line and use the same central ofiiee equipment.

While I have illustrated my invention in connection with automatic apparatus of a particular type, it will, of course, be understood that I do not wish to limit myself to the use of such apparatus, but that other forms of line switches and selectors can be employed, and various other changes and modifications can be made without departing from the spirit of my invention.

What I claim as my invention is 1. In a telephone system, a subscribers trunk line, and means by which either of said subscribers may obtain connection with said trunk and extend a connection thereover.

2. In a telephone system, a trunk line, a subscribers line provided with means for transmitting one character of impulses over said line, a second subscribcrs line provided with means for transmitting a different character of imymlses, means by which a connection can be established from either of said lines with said trunk, andmeans for then extending the connection from said trunk controlled by either of said types of impulses.

3. In a telephone system, a trunk line, a selector switch in which said trunk terminates, a repeating mechanism in said trunk, a plurality of subscribers lines adapted to be connected with said trunk, and means for bringing said repeating mechanism into operation only when certain of said subscribers seize said trunk.

4. In a telephone system, a trunk line, an

automatic switch connected with said trunk,

aplurality of subscribers lines, means for extending a connection-from said lines to said trunk, means for transmitting impulses from certain of said subscribers lines over said trunk to said switch, a repeating mechanism in said trunk, and means whereby said repeating mechanism repeats impulses received from other of said subscribers lines to said automatic switch.

5. In a telephone system, a trunk line. a repeater in said trunk, means for transmitting impulses of two characters to said trunk, means whereby impulses of one character pass directly through said trunk, and means whereby impulses of the other character will be repeated over said trunk by said repeater.

6. In a telephone system, a trunk line. a repeater in said trunk. means for transmitting in'ipulses of two characters to said trunk, means whereby impulses of one character pass directly through said trunk. and means whereby impulses of the other chur actor will be repeated over said trunk by said repeater and will be transformed into impulses ot' the first character.

7. In a telephone system, a first line. an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor. an automatic trunking switch for the first line and one for the second line. said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets. means for controlling said progressively movable switch from either line. coi'nprising a battery and also comprisin when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and when the second line is connected with the trunk comprising the two sides of the second line in series and the impulse sender of the second line. I

8. In a telephone system, a first line. an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating, therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the-trunk. line separate from the other side thereof and when the second line is connected with the trunk, comprising the two'sides of the second line in series, and thevimpulse sender of the second line, and comprising also two sides of the'trunk linein series.

9. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into' two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line With the trunk, means for operating said progressively mo able switch comprising, operating magnets, means for controlling said progressively movable switch from either line comprising a battery and'also comprising, when the first line is connected with the trunk, one. side of the first line separate from the other side of the first line and its impulse. sender, and one side of one section of the trunk line separate from the other side. thereof and when the second line is connected with the trunlc comprising the two sides of the second line in series, and comprising also two sides of one section of the trunk line.

10. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising also two sides of one section of the trunk line. in series and one side of the other section of the trunk separate from the other side of said other section.

11. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk. means for operating said progres-- sively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and alsocomprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender. and when the second line is connected with the trunk comprising. the two sides of the second line in series and the'impulse sender of the second line, and a relay for separating the two sections of the. trunk.

1:2. In a. telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a. second line, an impulse sender therefor, an automatic trunking, switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line. is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line'is connected with the trunk, comprising the two sides of the second line in Se ries, and the impulse sender of the second line, and comprising two sides of the trunk line in series, and a relay for separating the two sections of the trunk.

13. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively n'lovable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first Iinc separate from the other side of the first line and its impulse. sender, and one side of one section of the trunk line separate from the other side thereof and when the second line is connected with the trunk comprising the two sides of the second line in series, and comprising also two sides of one section of the trunk line, and a r day for separating the two sections of the trunk.

14. In a telephone system, a first line, an impulse sender for said line, a. progressively movableautomatic trunking switch, a. trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the firstline and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch con'iprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the. first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk comprising the two sides of the second line in series. and the. impulse sender of the second line, and com 'irising also two sides of one section of the trunk line in series and one side of the other section of the trunk separate from the other side of said other section, and a relay for separating the two sections of the trunk. .15. In a telephone system, a first line, an

impulse sender for said line, a progress-ivcl movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of sively movable the first line and its impulse sender, and when the second line is connected with the trunk comprising the two sides of the second line in series and the impulse sender of the second line, a relay for separating the two sections of the trunk, and a second relay for repeating the control impulses from one of the sections to the other.

I In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating gressively' movable switch comprising operating magnets, means for controlling said progressively movable switch line comprisin a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender. and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk, comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising two sides of the trunk line in series, a relay for separating the two sections of the trunk, and a second relay for repeating the control impulses from one of the sections to the other.

17. In a telephone system, a first line, an impulse sender for said first line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprisingoperating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of one section of the trunk line separate from the other side thereof and when the second line is connected with the trunk comprising the two sides of the second line in series, and comprising also two sides of one section of the trunk line, a relay for separating the two sections of the trunk, and a second relay for repeating the control impulses from one of the sections to the other.

18. In a telephone system, a first line, an impulse sender for said line, a progresautomatic trunking switch,

impulse said profrom either a trunk line. terminating therein and di vided into two sections, a second line, an

trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means 'for operating said progressively movable switch comprising magnets, means for ct-mtrolling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising also two sides of one section of the trunk line in series and one side of the other section of the trunk separate from the other side of said other section, a relay for separating the two sections of the trunk, and a second relay for repeating the control impulses from one of the sections to the other.

19. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, .a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line com- ,irising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and when the second line is connected with the trunk comprising the two sides of the second line in series and the impulse sender of the second line, a relay for separating the two sections of the trunk, and a second relay for repeating the control impi'dscs from one of the sections to the other, said second relay under the control of said first relay. a

20. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch,

a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor,

switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line w1th the trunk, means for operating said prosender therefor, an automatic an automatic trunking gressively movable switch comprising oper- I ating magnets, means for controlling said the progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk, comprising the two sides of the second line in series, and the impulse sender of second line, and comprising two sides of the trunk line in series, a relay for separating the two sections of the trunk, and a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay.

21. In a telephone system, a first llne, an impulse sender for said first line, a progressively mo able automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operatingsaid progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of one section of the trunk line separate from the other side thereof and when the second line is connected with the trunk comprising the two sides of the second line in series, and comprising also two sides of one section of the trunk line, a relay for separating the two sections of the trunk, and a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay.

22. In a telephone system, impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate fromthe other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk comprising the two a first line, an

' atlng magnets,

sides of the second line in series, and the impulse sender of the second line, and coinprising also two sides of one section of the trunk line in series and one side of the other section of the trunk separate from the other side of said other section,- a relay for separating the two sections of the trunk, and a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay.

23. In a telephone system, a. first line, an impulse sender for saidline, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising opermeans for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and when the second line is connected with the trunk comprising the two sides of the second line in series and the impulse sender of the second line, a relay for separating the two sections of the trunk, and a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay to connect the second relay with a section of the trunk.

24. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line selmrate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk, comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising two sides of the a. relay for separating the two sections of the trunk and a second relay for repeating the control impulses from one of the sections to trunk line in series,

Ctr

the other, said second relay under the control of said first relay to connect the second relay with a section of the trunk.

25. In a telephone system, a first line, an impulse sender for said first line, a progressively movable automatic trunking switch. a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connectml with the trunk, one side of the first line separate from the. other side of the first line and its impulse sender, and one side of one section of the trunk line separate from the other side thereof and when the second line is connected with the trunk comprising the two sides of the second line in series, and comprising also two sides of one section of the trunk line, a relay for separating the two sections of the trunk. and a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay to connect the second relay with a section of the trunk.

20. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections. a secondline, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means-for operating said progressively movable switch comprising; magnets. means for controlling said progressively movable switch from. either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line, separate from the other side thereof, and when the second line is connected with the. trunk comprising the two sides of the second line in series, and the impulse sender of: the second line, and comprising also two sides oi one section of the trunk line in series and one side of the other section of the trunk separate from the other side'ot' said other section, a relay for separating the two sections of the trunk, and a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay to connect the second relay with a section of the trunk.

27. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second. line, said trunk accessible to both of said switches for connecting either line two sections of the trunk, and a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of'said first relay to connect the second'relay with a section of the trunk, whereby the second relay is placed under line control.

28. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein'and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk, comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising two sides oi the trunk line in series, a relay for separating the two sec tions of the trunk and a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay to connect the second relay with a section of the trunk, whereby the second relay is placed under line control.

29. In a telephone system, a first line, an impulse sender for said first line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of one section of the trunk line se|iiarate from the other side thereof and when the second line is connected with the trunk comprising the two sides of the second line in series, and comprising also two sides of one section of the trunk line, a relay for separating the two sections of the trunk, and a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay to connect the second relay with a section of the trunk, whereby the second relay is placed under line control.

30. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising also two sides of one section of the trunk line in series and one side of the other section of the trunk separate from the other side of said other section, a relay for separating the two sections of the trunk, and a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay to connect the second relay with a section of the trunk, whereby the second relay is placed under line control.

31. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable. switch from either line comprising a battery and also comprising when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and when the second line is connected with the trunk comprising the two sides of the second line in series and the impulse sender of the second line, a relay for separating the two sections of the trunk,

and a control circuit from the tioned.

32. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse tender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk, comprising the two'sides of the. second line in series, and the impulse sender of the second line, and comprising two sides of the trunk line in series a relay for .se jiarating the two sections of the trunk, and a control circuit for said relay separate from the line and trunk conductors mentioned.

33. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively mo 'able switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising. when the first line is connected with the trunk, one side of the first line separate for said relay separate line and trunk conductors menfrom the other side of the first line and its impulse sender, and one side of one section of the trunk line separate from the other side thereof and when the second line is connected with the trunk comprising the two sides of the second line in series, and comprising also two sides of one section of the trunk line, a relay for separating the two sections of the trunk, and a control circuit for said relay separate from. the line and trunk conductors mentioned.

34. In a telephone system, av first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the .econd line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said. progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising also two sides of one section of the trunk line in series and one side of the other section of the trunk separatefrom the other side of said other section. a relay for separating the two sections of the trunk,

and a control circuit for said relay separate from the line and trunk conductors mentioned.

In a telephone system. a first line, an impulse sender for said line. a progressively movable automatic trunking switch. a trunk line tern'iinating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the sec ond line, said trunk accessible to both of said switches for connecting either line with the trunk. means for operating said progressively movable switch comprising operating magnets. means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side'of the first line and its impulse sender, and when the second line is connected wit-h the trunk comprising the two sides of the second line in series and the impulse sender of the second line, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, and a control circuit for said first relay separate from the line and trunk conductors mentioned.

36. In a telephone system, a. first line, an impulse sender for said line,- a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, asecond line, an impulse sender therefor, an automatic trunking switch for the. first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the sec ond line is connected with the trunk, comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising two sides of the trunk line in series. a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the. other. and a control circuit for said first relay separate from the line and trunk conductors mentioned.

37. In a telephone system, a first line, an impulse sender for said first line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable. switch comprising operating magnets, means for controlling said progressh-ely movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side. of the first line separate from the other side of the first line and its impulse sender, and one side of one section of the trunk line separate from the other side thereof and when the second line is connected with the trunk comprising the two sides of the second line in series, and comprising also two sides of one section of the trunk line, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, and a control circuit for said first relay separate from the line and trunk conductors mentioned.

38. In a telephone system, a first line, an impulse sender for said line, a progressively movable auton'ialiic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressivelymovable switch comprising magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising also two sides of one section of the trunk line in series and one side of the other section of the trunk separate from the other side of said other section, a relay for separating the tw sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, and a control circuit for said first relay separate from the line and trunk conductors mentioned. v

39. In a telephone system, a first line, an impulse sender for said line, a progressivel movable automatic trunking switch, a trun line terminating therein and divided 'into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and when the second line is connected with the trunk comprising the two sides of the second line in series and the impulse sender of the second line, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay, and a control circuit for said first relay separate from the line and trunk conductors mentioned.

40. In a telephone system, a first line, an impulse sender for said line, a. progressivel movable automatic trunking switch, a, t line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said switch for the first line and one for the sectrunk accessible to both of said switches for switch comprising operating magnets, means for controlling said progressively movable switch from either line comprisin a battery and .also comprising, when the rst line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk, com risin the two sides of the second line in serles, an the impulse sender of the second line, and comprising two sides of the trunk line in series, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, said second relay under the con-- trol of said first relay, and a control circuit for said first relay separate from the line and trunk conductors mentioned. I 41. In a telephone system, a-first 1ine, an impulse sender for said first line, a progressively movable automatic trunkin switch, a trunk line terminating therein an divided into two sections, a second line, an im pulse sender therefor, an automatic trunking 0nd line, said trunk accessible to both of said switches, for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for control ing said progressively movable switch from either hne comprising abattery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of one section of the trunk line separate from the other side therc of and when the second line is connected with the trunk comprising two sides of the second line in series, and comprising also two sides of one section of the trunk line, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, said second relay under the con- 5 trol of said first relay, and a control circuit for said first relay separate from the line and trunk conductors mentioned.

42. In a telephone system, a'first line, an impulse sender for said line, a progres- 20 sively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the 5 second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for o crating said progressively movable switc comprising magnets, means for controlling sai'dprogres- 130 sively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising also two sides of one section of the trunk line in series and one side of the other section of the trunk separate from the other side of said other section, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay, and a control circuit for said first relay separate from the line and trunk conductors mentioned.

43. In a. telephone system, a first line, an

impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an. impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means foroperating said progressively movable-switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and when the second line is connected with the trunk comprising the two sides of the second line in series and the impulse sender of the second line, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay to connect the second relay with a section of the trunk, and a control circuit for said first relay separate from the line-and trunk conductors mentioned.

4L4. In a telephone system, a first line, an impulse. sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line,

said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one

side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk, comprising the two sides of the second line in series, and the impulse sender of the sec,

ond line, and comprising two sides of the trunk in series, a relay for separating the two sections of the trunk and a second relay for repeating the control impulses from one a trunk line terminating therein and divlded into two sections, a second line, an

impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of one section of the trunk line separate from the other side thereof, and when the second line is connected with the trunk comprising the two sides of the second line in series, and comprising also two sides of one section of the trunk line, a relay for separat ing the tWo sections of the trunk, a second relay for repeating the control imipulses from one of the sections to the other, said second relay under the control of said first relay to connect the second relay with a section of the trunk, and a control circuit for said first relay separate from the line and trunk conductors mentioned. V 46. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line. and its impulse sender, and one side of the trunk line separate from the other side thereof, and whenthe second line is connected with the trunk comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising also two sides of one section of the trunk line in series and one side of the other section of the trunk separate from the other side of said other section, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said firstrelay to connect the second relay with a section of the trunk, and a control circuit for said first relay separate from the line and trunk conductors mentioned.

47. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprislng a battery and also comprising, when the first line is connected'with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and when the second line is connected with the trunk comprising the two sides-of the second line in series and the impulse sender of the sec- 0nd line, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay to connect the Second relay with a section of the trunk, whereby the second relay is placed under line control, and a control circuit for said first relay separate from the line and trunk conductors mentioned.

48. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic'trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulsesender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk, comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising two Sides of the trunk line in series, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other,

said second relay under the control of said first relay to connect the second relay with a section of the trunk, whereby the second relay is placed under line control, and a control circuit for said first relay separate from the line and trunk conductors mentioned.

49. In a telephone system, a first line, an

impulse sender for said first line, a progresmagnets, means for controlling said progressively movable switch from either line com-.

prising a battery and also conprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender,

and one side of one section of the trunk line separate from the other side thereof, and when the second line is connected with the trunk comprising the two sides of the second line in series, and comprising also two sides of one section of the trunk line, a relay for separatin the two sections of the trunk, a second re ay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay to connect the second relay with a section of the trunk, whereby-the second relay is placed under line control, and a control circuit for said first relay separate from the line and trunk conductors mentioned.

50. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second. line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is con nected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control'of said first relay to connect the second relay with a section of the trunk, whereby the second relay is placed under line control, and a control circuit for -said first relay separate from the line and trunk conductors mentioned.

51. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second l.ine,-an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and

when the second line is connected with the trunk comprising the two sides of the second line in series and the impulse sender of the second line, a relay for separating the two S ections of the trunk, and a control circuit for said relay separate from the line and trunk conductors mentioned, said control circuit under the control of one of said switches.

52. In a telephone system, a first line, an

- impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk,

- means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other Side thereof, and when the second line is connected with the trunk, comprising the two sides of the second line in series, and the impulse sender'of the second line, and comprising two sides of the trunk line in series,

a relay for separating the two sections of the trunk, and a control circuit for said relay separate'from the line and trunk conductors mentioned, said control circuit under the control of one of said switches.

53. In a telephone system, a first line,

an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for they first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating saidprogres sively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprisin when the first line is connected with the trunk, one side of the first line separate from the other side of the. first line and its impulse sender, and one side of one section of the trunk line separate from the other side thereof and when the second line is connected with the trunk comprising the two sides of the second line in series, and comprising also two sides of one section of the trunk line, a relay forseparating the two sections of the trunk, and a control circuit for said relay separate from the line and trunk conductors mentioned, said control circuit under the control of one of said switches.

54. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate'from the other side thereof, and when the second line is connected with the trunk comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising also two sides of one section of the trunk line in series and one side of the other section of the trunk separate from the other side of said other section, a relay for separating the two sections of the trunk, and a control circuit for said relay separate from the line and trunk conductors mentioned, said control circuit under the control of one of said switches.

55. In a telephone system, a first line, an

impulse sender for said line, a progressively switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and when the second line is connected with the trunk comprising the two sides of the second line in series and the impulse sender of the second line, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, and a control circuit for said first relay separate from the line and trunk conductors mentioned, said control circuit under the control of one of said switches. 56. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trun line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk, comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising two sides of the trunk line in series, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, and a control circuit for said first relay separate from the line and trunk conductors mentioned, said control circuit under the control of one ofsaid switches.

57. In a telephone system, a first line, an impulse sender for said first line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of ed with the trunk comprising the two sides of the second line in series, and comprising also two sides of one section of the trunk line, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, and a control circuit for said first relay separate from the line and trunk conductors mentioned, said control circuit under the control of one of said switches.

58. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising also two sides of one section of the trunk line in series and one side of the other section of the trunk separate from the other side of said other section, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, and a control circuit for said first relay separate from the line anditrunk conductors mentioned, said control circuit under the control of one of said switches.

59. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable 1,21c,aep

switch comprising operating magnets, means for controlling said progressively movable switch from either line comp-risin a battery and also comprising, when the rst line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and when the second line is connected with the trunk comprising the two sides of the second line in series and the impulse sender of the second line, a relay for separating the two sec tions of the trunk, a second relay for repeat ing the control impulses from'one of the sections to the other, said second relay under the control of said first relay, and a control circuit for said first relay separate from the line and trunk conductors mentioned, said control circuit under the control of one of said switches.

60., In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk, comprising the two sides of the second line in series, and the impulse sender of the second line, and compris ing two sides of the trunk line in series, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay, and a control circuit for said first relay separate from the line and trunk conductors mentioned, said control circuit under the control of one of said switches.

61. In a telephone system, a first line, an impulse sender for said fi'rstline, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, asecond line, an impulse sender therefor, switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected an automatic trunking,

with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of one section of the trunk line separate from the other side thereof and when the second line is connected with the trunk comprising two sides of the second line in series, and comprising also two sides of one section of the trunk line, a relay forseparating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay, and acontrol circuit for said first relay separate from the line and trunk conductors mentioned, said control circuit under the control of one of said switches.

62. In a telephone system, a impulse senderfor said line, movable automatic trunking switch, a trunk line terminating therein and divided into two sections, therefor, an automatic trunking switch for. the first line and one for the second line, said trunk accessible to both of said switches first line, an

for connecting either line with the trunk,

a progressively a second line, an impulse sender i means for operating said progressively movable switch comprising magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, oneside of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising also two sides of one section of the trunk line in series and one the other section of the trunkseparate from the other side of said other section, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, said second relay under the first relay, and a. control circuit for said first relay separate from the line and trunk conductors mentioned, said control circuit under the control of one of said switches.

63. In a telephone s stem, a first line, an impulse sender for sai line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising,

control oi'said 105 side .of

' when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and when the second line is connected with the trunk comprising the two sides of the second line in series and the impulse sender of the second line, arelay=,for separating the two sections of the.

trunk, a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay to connect the second relay with a section of the trunk, and a control circuit for said first relay separate from the line and trunk conductors mentioned, said control circuit underthe control of one of said switches.

64. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sendertherefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk, con'iprising the two sides of the second line in series, and the impulse sender of the second line, and comprising two sides of the trunk in series, a relay for separatin the two sections of the trunk and a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay-to connect the second relay with a section of the trunk, and a control circuit for said first relay separate from the line and trunk conductors mentioned, said control circuit under the control of one of said switches.

65. In a telephone system, a first line, an impulse sender for said first line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising operating magnets, means for controlling said progressively movable switch from either line comprising a battery and also with the trunk, one side of the first line separate from the other side of the first line and its impulse sender, and one side of one section of the trunk line separate from the other side thereof, and when the second line is connected with the trunk comprising the two sides of the second line in series, and comprising also two sides of one section of the trunk line, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said .first relay to connect the second relay with a section of the trunk, and a control circuit for said first relay separate from the line and trunk conductors mentioned, said control circuit under the control of one of said switches.

66. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, a trunk line terminating therein and divided into two sections, a second line, an impulse sender therefor, an automatic trunking switch for the first line and one for the second line, said trunk accessible to both of said switches for connecting either line with the trunk, means for operating said progressively movable switch comprising magnets, means for controlling said progressively movable switch from either line comprising a battery and also comprising, when the first line is connected with the trunk, one. side of the first line separate from the other side of the first line and its impulse sender, and one side of the trunk line separate from the other side thereof, and when the second line is connected with the trunk comprising the two sides of the second line in series, and the impulse sender of the second line, and comprising also two sides of one section of the trunk line in series and one side of the other section of the trunk separate from the other side of said other section, a relay for separating the two sections of the trunk, a second relay for repeating the control impulses from one of the sections to the other, said second relay under the control of said first relay to connect the second relay with a section of the trunk, and a control circuit for said first relay separate from the line and trunk conductors mentioned, said control circuit under the control of one of said switches.

67. In a telephone system, a first line, an impulse sender for said line, a progressively movable automatic trunking switch, 

